text: """
  """
  from __future__ import absolute_import
  
  from ..unitquantity import UnitQuantity
  from .time import s
  from .mass import kg
  from .energy import J
  from .electromagnetism import coulomb
  
  
  Bq = becquerel = UnitQuantity(
      'becquerel',
      1/s,
      symbol='Bq',
      aliases=['becquerels']
  )
  Ci = curie = UnitQuantity(
      'curie',
      3.7e10*becquerel,
      symbol='Ci',
      aliases=['curies']
  )
  rd = rutherford = UnitQuantity(
      'rutherford',
      1e6*Bq,
      symbol='Rd',
      aliases=['rutherfords'],
      doc='this unit is obsolete, in favor of 1e6 Bq'
  )
  Gy = gray = Sv = sievert = UnitQuantity(
      'gray',
      J/kg,
      symbol='Gy',
      aliases=['grays', 'Sv', 'sievert', 'sieverts']
  )
  rem = UnitQuantity(
      'rem',
      1e-2*sievert,
      aliases=['rems']
  )
  rads = UnitQuantity(
      'rads',
      1e-2*gray,
      doc='''
      rad is commonly used symbol for radian. 
      rads unit of radiation is deprecated.
      '''
  )
  R = roentgen = UnitQuantity(
      'roentgen',
      2.58e-4*coulomb/kg,
      symbol='R',
      aliases=['roentgens']
  )
  
  del UnitQuantity, s, kg, J, coulomb
  